Siloxane compound and process for producing the same

ABSTRACT

A siloxane compound comprises a plurality of siloxane repeating units and at least a portion of the siloxane repeating units are cyclosiloxane repeating units conforming to a specified structure. A process for producing such siloxane compounds is also provided. A process and kit for producing a cross-linked silicone polymer using the described siloxane compounds is also provided. A light emitting diode (LED) comprises an encapsulant, and the encapsulant comprises a cross-linked silicone polymer produced from the described siloxane compounds.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims, pursuant to 35 U.S.C. §119(e), the benefit ofthe filing date of U.S. Patent Application No. 61/811,483, which wasfiled on Apr. 12, 2013.

TECHNICAL FIELD

This application relates to siloxane compounds (e.g., siloxane oligomersand siloxane compounds), cross-linked silicone polymers, and processesfor the producing the same.

BACKGROUND

Siloxane compounds and silicones have found many uses in modernindustry. For example, siloxane compounds are widely used in theproduction of cross-linked silicone polymers. These polymers typicallyare produced by either a hydrosilylation reaction or a condensationreaction. In the hydrosilylation reaction, siloxane compounds bearingvinyl groups undergo addition to link individual molecules of thecompounds through the formation of new Si—C bonds. The hydrosilylationreaction typically is catalyzed by platinum, which contributes to thecost of these polymers because the platinum cannot be recovered from thecured elastomer. In the condensation reaction, the siloxane compoundsreact in a condensation reaction to form new Si—O—Si linkages betweenindividual molecules. This condensation reaction produces volatileorganic compounds (VOCs) as a by-product.

Cross-linked silicone polymers can be used as sealants or encapsulantsfor electronics. In particular, cross-linked silicone polymers can beused as encapsulants for light emitting diodes (LEDs). Thesecross-linked silicone polymers are desirable because they do notinterfere with the operation of the electronic components. However, thecross-linked silicone polymers that exhibit sufficiently hightemperature stability to be used as encapsulants for higher power LEDsdo not have a high refractive index. This lower refractive index meansthat the light output from the LED will be reduced due to internalreflections in the semiconductor die of the LED.

A need remains for siloxane compounds that are suitable for use inmaking cross-linked silicone polymers without generating a large amountof volatile reaction products, such as the carbon-containing VOC'sproduced by condensation cure cross-linked silicone polymers. A needalso remains for siloxane compounds and cross-linked silicone polymersthat exhibit a high refractive index and are therefore better suited foruse in those applications that demand an encapsulant material exhibitinga high refractive index (e.g., LED encapsulant applications). A needalso remains for processes for generating these siloxane compounds andcross-linked silicone polymers. The subject matter described in thepresent application seeks to address these and other needs.

BRIEF SUMMARY OF THE INVENTION

In a first embodiment, the invention provides a siloxane compoundcomprising a plurality of siloxane repeating units, wherein about 10mol. % or more of the siloxane repeating units are cyclotrisiloxanerepeating units, and the cyclotrisiloxane repeating units areindependently selected from the group consisting of cyclotrisiloxanerepeating units conforming to the structure of Formula (I) below:

wherein R₁ and R₂ are independently selected from the group consistingof alkyl groups, substituted alkyl groups, cycloalkyl groups,substituted cycloalkyl groups, alkenyl groups, substituted alkenylgroups, cycloalkenyl groups, substituted cycloalkenyl groups,heterocyclyl groups, substituted heterocyclyl groups, aryl groups,substituted aryl groups, heteroaryl groups, substituted heteroarylgroups, trialkylsiloxy groups, aryldialkylsiloxy groups,alkyldiarylsiloxy groups, and triarylsiloxy groups; R₃ and R₄ areindependently selected from the group consisting of alkyl groups,substituted alkyl groups, alkanediyl groups, substituted alkanediylgroups, cycloalkyl groups, substituted cycloalkyl groups, alkenylgroups, substituted alkenyl groups, alkenediyl groups, substitutedalkenediyl groups, cycloalkenyl groups, substituted cycloalkenyl groups,heterocyclyl groups, substituted heterocyclyl groups, aryl groups,substituted aryl groups, heteroaryl groups, substituted heteroarylgroups, trialkylsiloxy groups, aryldialkylsiloxy groups,alkyldiarylsiloxy groups, and triarylsiloxy groups; provided, if one ofR₃ and R₄ is selected from the group consisting of alkanediyl groups,substituted alkanediyl groups, alkenediyl groups, and substitutedalkenediyl groups, then the other of R₃ and R₄ is also selected from thegroup consisting of alkanediyl groups, substituted alkanediyl groups,alkenediyl groups, and substituted alkenediyl groups, and R₃ and R₄ arebonded to form a cyclic moiety.

In a second embodiment, the invention provides a process for producing asiloxane compound, the process comprising the steps of:

(a) providing a first siloxane compound, the first siloxane compoundcomprising at least one segment conforming to the structure of Formula(XX)

wherein R₁ and R₂ are independently selected from the group consistingof alkyl groups, substituted alkyl groups, cycloalkyl groups,substituted cycloalkyl groups, alkenyl groups, substituted alkenylgroups, cycloalkenyl groups, substituted cycloalkenyl groups,heterocyclyl groups, substituted heterocyclyl groups, aryl groups,substituted aryl groups, heteroaryl groups, substituted heteroarylgroups, trialkylsiloxy groups, aryldialkylsiloxy groups,alkyldiarylsiloxy groups, and triarylsiloxy groups; R₂₀ and R₂₁ areindependently selected from the group consisting of hydrogen, alkylgroups, substituted alkyl groups, alkanediyl groups, substitutedalkanediyl groups, cycloalkyl groups, substituted cycloalkyl groups,alkenyl groups, substituted alkenyl groups, alkenediyl groups,substituted alkenediyl groups, cycloalkenyl groups, substitutedcycloalkenyl groups, heterocyclyl groups, substituted heterocyclylgroups, aryl groups, substituted aryl groups, heteroaryl groups,substituted heteroaryl groups, trialkylsiloxy groups, aryldialkylsiloxygroups, alkyldiarylsiloxy groups, and triarylsiloxy groups; providedonly one of R₂₀ and R₂₁ can be hydrogen; and further provided, if one ofR₂₀ and R₂₁ is selected from the group consisting of alkanediyl groups,substituted alkanediyl groups, alkenediyl groups, and substitutedalkenediyl groups, then the other of R₂₀ and R₂₁ is also selected fromthe group consisting of alkanediyl groups, substituted alkanediylgroups, alkenediyl groups, and substituted alkenediyl groups, and R₂₀and R₂₁ are bonded to form a cyclic moiety; x is 0 or any positiveinteger;

(b) providing an organosilicon compound conforming to the structure ofFormula (XXX)

wherein R₃ and R₄ are independently selected from the group consistingof alkyl groups, substituted alkyl groups, alkanediyl groups,substituted alkanediyl groups, cycloalkyl groups, substituted cycloalkylgroups, alkenyl groups, substituted alkenyl groups, alkenediyl groups,substituted alkenediyl groups, cycloalkenyl groups, substitutedcycloalkenyl groups, heterocyclyl groups, substituted heterocyclylgroups, aryl groups, substituted aryl groups, heteroaryl groups,substituted heteroaryl groups, trialkylsiloxy groups, aryldialkylsiloxygroups, alkyldiarylsiloxy groups, and triarylsiloxy groups; provided, ifone of R₃ and R₄ is selected from the group consisting of alkanediylgroups, substituted alkanediyl groups, alkenediyl groups, andsubstituted alkenediyl groups, then the other of R₃ and R₄ is alsoselected from the group consisting of alkanediyl groups, substitutedalkanediyl groups, alkenediyl groups, and substituted alkenediyl groups,and R₃ and R₄ are bonded to form a cyclic moiety; R₃₀ and R₃₁ areindependently selected from the group consisting of hydrogen, alkylgroups, substituted alkyl groups, acyl groups, and substituted acylgroups; and y is a positive integer from 1 to 6;

(c) providing a reaction phase comprising a Lewis acid catalyst and asolvent;

(d) combining the first siloxane compound and the organosilicon compoundin the reaction phase under conditions so that the first siloxanecompound and the organosilicon compound react in a condensation reactionto produce a second siloxane compound, the second siloxane compoundcomprising at least one segment conforming to the structure of Formula(XL)

In a third embodiment, the invention provides a siloxane compoundcomprising a plurality of siloxane repeating units, wherein at least aportion of the siloxane repeating units are cyclosiloxane repeatingunits, and the cyclosiloxane repeating units are independently selectedfrom the group consisting of cyclosiloxane repeating units conforming tothe structure of Formula (XL)

wherein R₁ and R₂ are independently selected from the group consistingof alkyl groups, substituted alkyl groups, cycloalkyl groups,substituted cycloalkyl groups, alkenyl groups, substituted alkenylgroups, cycloalkenyl groups, substituted cycloalkenyl groups,heterocyclyl groups, substituted heterocyclyl groups, aryl groups,substituted aryl groups, heteroaryl groups, substituted heteroarylgroups, trialkylsiloxy groups, aryldialkylsiloxy groups,alkyldiarylsiloxy groups, and triarylsiloxy groups; R₂₀ and R₂₁ areindependently selected from the group consisting of hydrogen, alkylgroups, substituted alkyl groups, alkanediyl groups, substitutedalkanediyl groups, cycloalkyl groups, substituted cycloalkyl groups,alkenyl groups, substituted alkenyl groups, alkenediyl groups,substituted alkenediyl groups, cycloalkenyl groups, substitutedcycloalkenyl groups, heterocyclyl groups, substituted heterocyclylgroups, aryl groups, substituted aryl groups, heteroaryl groups,substituted heteroaryl groups, trialkylsiloxy groups, aryldialkylsiloxygroups, alkyldiarylsiloxy groups, and triarylsiloxy groups; providedonly one of R₂₀ and R₂₁ can be hydrogen; and further provided, if one ofR₂₀ and R₂₁ is selected from the group consisting of alkanediyl groups,substituted alkanediyl groups, alkenediyl groups, and substitutedalkenediyl groups, then the other of R₂₀ and R₂₁ is also selected fromthe group consisting of alkanediyl groups, substituted alkanediylgroups, alkenediyl groups, and substituted alkenediyl groups, and R₂₀and R₂₁ are bonded to form a cyclic moiety; R₃ and R₄ are independentlyselected from the group consisting of haloalkyl groups, aralkyl groups,aryl groups, substituted aryl groups, heteroaryl groups, and substitutedheteroaryl groups; x is 0 or any positive integer; and y is a positiveinteger from 1 to 6.

In a fourth embodiment, the invention provides a compound conforming tothe structure of Formula (LXX)

wherein R₇₀ and R₇₁ are independently selected from the group consistingof haloalkyl groups, aralkyl groups, aryl groups, substituted arylgroups, heteroaryl groups, and substituted heteroaryl groups; c is 0 ora positive integer from 1 to 3; R₇₂, R₇₃, R₇₄, R₇₅, R₇₆, R₇₇, R₇₈, R₈₀,R₈₁, R₈₂, R₈₃, R₈₄, R₈₅, and R₈₆ are independently selected from thegroup consisting of alkyl groups, substituted alkyl groups, cycloalkylgroups, substituted cycloalkyl groups, alkenyl groups, substitutedalkenyl groups, cycloalkenyl groups, substituted cycloalkenyl groups,heterocyclyl groups, substituted heterocyclyl groups, aryl groups,substituted aryl groups, heteroaryl groups, substituted heteroarylgroups, trialkylsiloxy groups, aryldialkylsiloxy groups,alkyldiarylsiloxy groups, and triarylsiloxy groups; provided, if c is 0,then R₇₄ and R₈₂ are independently selected from the group consisting ofhaloalkyl groups, aralkyl groups, aryl groups, substituted aryl groups,heteroaryl groups, and substituted heteroaryl groups.

In a fifth embodiment, the invention provides a process for producing across-linked silicone polymer, the process comprising the steps of:

(a) providing a first siloxane compound, the first siloxane compoundcomprising a plurality of repeating units conforming to the structure ofFormula (XL)

wherein R₁ and R₂ are independently selected from the group consistingof alkyl groups, substituted alkyl groups, cycloalkyl groups,substituted cycloalkyl groups, alkenyl groups, substituted alkenylgroups, cycloalkenyl groups, substituted cycloalkenyl groups,heterocyclyl groups, substituted heterocyclyl groups, aryl groups,substituted aryl groups, heteroaryl groups, substituted heteroarylgroups, trialkylsiloxy groups, aryldialkylsiloxy groups,alkyldiarylsiloxy groups, and triarylsiloxy groups; R₃ and R₄ areindependently selected from the group consisting of alkyl groups,substituted alkyl groups, alkanediyl groups, substituted alkanediylgroups, cycloalkyl groups, substituted cycloalkyl groups, alkenylgroups, substituted alkenyl groups, alkenediyl groups, substitutedalkenediyl groups, cycloalkenyl groups, substituted cycloalkenyl groups,heterocyclyl groups, substituted heterocyclyl groups, aryl groups,substituted aryl groups, heteroaryl groups, substituted heteroarylgroups, trialkylsiloxy groups, aryldialkylsiloxy groups,alkyldiarylsiloxy groups, and triarylsiloxy groups; provided, if one ofR₃ and R₄ is selected from the group consisting of alkanediyl groups,substituted alkanediyl groups, alkenediyl groups, and substitutedalkenediyl groups, then the other of R₃ and R₄ is also selected from thegroup consisting of alkanediyl groups, substituted alkanediyl groups,alkenediyl groups, and substituted alkenediyl groups, and R₃ and R₄ arebonded to form a cyclic moiety; R₂₀ and R₂₁ are independently selectedfrom the group consisting of hydrogen, alkyl groups, substituted alkylgroups, alkanediyl groups, substituted alkanediyl groups, cycloalkylgroups, substituted cycloalkyl groups, alkenyl groups, substitutedalkenyl groups, alkenediyl groups, substituted alkenediyl groups,cycloalkenyl groups, substituted cycloalkenyl groups, heterocyclylgroups, substituted heterocyclyl groups, aryl groups, substituted arylgroups, heteroaryl groups, substituted heteroaryl groups, trialkylsiloxygroups, aryldialkylsiloxy groups, alkyldiarylsiloxy groups, andtriarylsiloxy groups; provided only one of R₂₀ and R₂₁ can be hydrogen;and further provided, if one of R₂₀ and R₂₁ is selected from the groupconsisting of alkanediyl groups, substituted alkanediyl groups,alkenediyl groups, and substituted alkenediyl groups, then the other ofR₂₀ and R₂₁ is also selected from the group consisting of alkanediylgroups, substituted alkanediyl groups, alkenediyl groups, andsubstituted alkenediyl groups, and R₂₀ and R₂₁ are bonded to form acyclic moiety; x is 0 or a positive integer from 1 to 6; and y is apositive integer from 1 to 6;

(b) providing a ring-opening catalyst;

(c) combining the first siloxane compound and the ring-opening catalystto produce a reaction mixture;

(d) reacting the components in the reaction mixture under conditionssuch that (i) the ring-opening catalyst opens at least a portion of therepeating units conforming to the structure of Formula (XL) in the firstsiloxane compound to form cross-linking groups and (ii) at least aportion of the cross-linking groups react with other molecules of thefirst siloxane compound to produce cross-links between molecules therebyforming a cross-linked silicone polymer.

In a sixth embodiment, the invention provides a kit for producing across-linked silicone polymer, the kit comprising a first part and asecond part, the first part and second part being physically isolatedfrom each other until such time as they are mixed to produce across-linked silicone polymer, wherein:

(a) the first part comprises a first siloxane compound, the firstsiloxane compound comprising a plurality of repeating units conformingto the structure of Formula (XL)

wherein R₁ and R₂ are independently selected from the group consistingof alkyl groups, substituted alkyl groups, cycloalkyl groups,substituted cycloalkyl groups, alkenyl groups, substituted alkenylgroups, cycloalkenyl groups, substituted cycloalkenyl groups,heterocyclyl groups, substituted heterocyclyl groups, aryl groups,substituted aryl groups, heteroaryl groups, substituted heteroarylgroups, trialkylsiloxy groups, aryldialkylsiloxy groups,alkyldiarylsiloxy groups, and triarylsiloxy groups; R₃ and R₄ areindependently selected from the group consisting of alkyl groups,substituted alkyl groups, alkanediyl groups, substituted alkanediylgroups, cycloalkyl groups, substituted cycloalkyl groups, alkenylgroups, substituted alkenyl groups, alkenediyl groups, substitutedalkenediyl groups, cycloalkenyl groups, substituted cycloalkenyl groups,heterocyclyl groups, substituted heterocyclyl groups, aryl groups,substituted aryl groups, heteroaryl groups, substituted heteroarylgroups, trialkylsiloxy groups, aryldialkylsiloxy groups,alkyldiarylsiloxy groups, and triarylsiloxy groups; provided, if one ofR₃ and R₄ is selected from the group consisting of alkanediyl groups,substituted alkanediyl groups, alkenediyl groups, and substitutedalkenediyl groups, then the other of R₃ and R₄ is also selected from thegroup consisting of alkanediyl groups, substituted alkanediyl groups,alkenediyl groups, and substituted alkenediyl groups, and R₃ and R₄ arebonded to form a cyclic moiety; R₂₀ and R₂₁ are independently selectedfrom the group consisting of hydrogen, alkyl groups, substituted alkylgroups, alkanediyl groups, substituted alkanediyl groups, cycloalkylgroups, substituted cycloalkyl groups, alkenyl groups, substitutedalkenyl groups, alkenediyl groups, substituted alkenediyl groups,cycloalkenyl groups, substituted cycloalkenyl groups, heterocyclylgroups, substituted heterocyclyl groups, aryl groups, substituted arylgroups, heteroaryl groups, substituted heteroaryl groups, trialkylsiloxygroups, aryldialkylsiloxy groups, alkyldiarylsiloxy groups, andtriarylsiloxy groups; provided only one of R₂₀ and R₂₁ can be hydrogen;and further provided, if one of R₂₀ and R₂₁ is selected from the groupconsisting of alkanediyl groups, substituted alkanediyl groups,alkenediyl groups, and substituted alkenediyl groups, then the other ofR₂₀ and R₂₁ is also selected from the group consisting of alkanediylgroups, substituted alkanediyl groups, alkenediyl groups, andsubstituted alkenediyl groups, and R₂₀ and R₂₁ are bonded to form acyclic moiety; x is 0 or a positive integer from 1 to 6; and y is apositive integer from 1 to 6; and

(b) the second part comprises a ring-opening catalyst.

In a seventh embodiment, the invention provides a light-emitting diodecomprising:

(a) a semiconductor crystal, the semiconductor crystal comprising ann-type semiconductor material in a first region of the semiconductorcrystal, a p-type semiconductor material in a second region of thesemiconductor crystal, and a p-n junction at the boundary between thefirst region and the second region of the semiconductor material;

(b) a cathode electrically connected to the first region of thesemiconductor crystal,

(c) an anode electrically connected to the second region of thesemiconductor crystal, and

(d) an encapsulant material surrounding the semiconductor crystal, theencapsulant material comprising a cross-linked silicone polymer producedby a process comprising the steps of:

-   -   (i) providing a first siloxane compound, the first siloxane        compound comprising a plurality of repeating units conforming to        the structure of Formula (XL)

-   -   wherein R₁ and R₂ are independently selected from the group        consisting of alkyl groups, substituted alkyl groups, cycloalkyl        groups, substituted cycloalkyl groups, alkenyl groups,        substituted alkenyl groups, cycloalkenyl groups, substituted        cycloalkenyl groups, heterocyclyl groups, substituted        heterocyclyl groups, aryl groups, substituted aryl groups,        heteroaryl groups, substituted heteroaryl groups, trialkylsiloxy        groups, aryldialkylsiloxy groups, alkyldiarylsiloxy groups, and        triarylsiloxy groups; R₂₀ and R₂₁ are independently selected        from the group consisting of hydrogen, alkyl groups, substituted        alkyl groups, alkanediyl groups, substituted alkanediyl groups,        cycloalkyl groups, substituted cycloalkyl groups, alkenyl        groups, substituted alkenyl groups, alkenediyl groups,        substituted alkenediyl groups, cycloalkenyl groups, substituted        cycloalkenyl groups, heterocyclyl groups, substituted        heterocyclyl groups, aryl groups, substituted aryl groups,        heteroaryl groups, substituted heteroaryl groups, trialkylsiloxy        groups, aryldialkylsiloxy groups, alkyldiarylsiloxy groups, and        triarylsiloxy groups; provided only one of R₂₀ and R₂₁ can be        hydrogen; and further provided, if one of R₂₀ and R₂₁ is        selected from the group consisting of alkanediyl groups,        substituted alkanediyl groups, alkenediyl groups, and        substituted alkenediyl groups, then the other of R₂₀ and R₂₁ is        also selected from the group consisting of alkanediyl groups,        substituted alkanediyl groups, alkenediyl groups, and        substituted alkenediyl groups, and R₂₀ and R₂₁ are bonded to        form a cyclic moiety; x is 0 or a positive integer from 1 to 6;        and y is a positive integer from 1 to 6;    -   (ii) providing a ring-opening catalyst;    -   (iii) combining the first siloxane compound and the ring-opening        catalyst to produce a reaction mixture;    -   (iv) reacting the components in the reaction mixture under        conditions such that (A) the ring-opening catalyst opens at        least a portion of the repeating units conforming to the        structure of Formula (XL) in the first siloxane compound to form        cross-linking groups and (B) at least a portion of the        cross-linking groups react with other molecules of the first        siloxane compound to produce cross-links between molecules        thereby forming a cross-linked silicone polymer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, cross-sectional representation of a lightemitting diode (LED) according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The following definitions are provided to define several of the termsused throughout this application.

As used herein, the term “substituted alkyl groups” refers to univalentfunctional groups derived from substituted alkanes by removal of ahydrogen atom from a carbon atom of the alkane. In this definition, theterm “substituted alkanes” refers to compounds derived from acyclicunbranched and branched hydrocarbons in which (1) one or more of thehydrogen atoms of the hydrocarbon is replaced with a non-hydrogen atom(e.g., a halogen atom) or a non-alkyl functional group (e.g., hydroxygroup, aryl group, heteroaryl group) and/or (2) the carbon-carbon chainof the hydrocarbon is interrupted by an oxygen atom (as in an ether) ora sulfur atom (as in a sulfide).

As used herein, the term “substituted cycloalkyl groups” refers tounivalent functional groups derived from substituted cycloalkanes byremoval of a hydrogen atom from a carbon atom of the cycloalkane. Inthis definition, the term “substituted cycloalkanes” refers to compoundsderived from saturated monocyclic and polycyclic hydrocarbons (with orwithout side chains) in which (1) one or more of the hydrogen atoms ofthe hydrocarbon is replaced with a non-hydrogen atom (e.g., a halogenatom) or a non-alkyl functional group (e.g., hydroxy group, aryl group,heteroaryl group) and/or (2) the carbon-carbon chain of the hydrocarbonis interrupted by an oxygen atom, a nitrogen atom, or a sulfur atom.

As used herein, the term “alkenyl groups” refers to univalent functionalgroups derived from acyclic, unbranched and branched olefins (i.e.,hydrocarbons having one or more carbon-carbon double bonds) by removalof a hydrogen atom from a carbon atom of the olefin.

As used herein, the term “substituted alkenyl groups” refers tounivalent functional groups derived from acyclic, substituted olefins byremoval of a hydrogen atom from a carbon atom of the olefin. In thisdefinition, the term “substituted olefins” refers to compounds derivedfrom acyclic, unbranched and branched hydrocarbons having one or morecarbon-carbon double bonds in which (1) one or more of the hydrogenatoms of the hydrocarbon is replaced with a non-hydrogen atom (e.g., ahalogen atom) or a non-alkyl functional group (e.g., hydroxy group, arylgroup, heteroaryl group) and/or (2) the carbon-carbon chain of thehydrocarbon is interrupted by an oxygen atom (as in an ether) or asulfur atom (as in a sulfide).

As used herein, the term “cycloalkenyl groups” refers to univalentfunctional groups derived from cyclic olefins (i.e., non-aromatic,monocyclic and polycyclic hydrocarbons having one or more carbon-carbondouble bonds) by removal of a hydrogen atom from a carbon atom of theolefin. The carbon atoms in the cyclic olefins can be substituted withalkyl groups and/or alkenyl groups.

As used herein, the term “substituted cycloalkenyl groups” refers tounivalent functional groups derived from substituted cyclic olefins byremoval of a hydrogen atom from a carbon atom of the cyclic olefin. Inthis definition, the term “substituted cyclic olefins” refers tocompounds derived from non-aromatic, monocyclic and polycyclichydrocarbons having one or more carbon-carbon double bonds in which oneor more of the hydrogen atoms of the hydrocarbon is replaced with anon-hydrogen atom (e.g., a halogen atom) or a non-alkyl functional group(e.g., hydroxy group, aryl group, heteroaryl group).

As used herein, the term “heterocyclyl groups” refers to univalentfunctional groups derived from heterocyclic compounds by removal of ahydrogen atom from an atom in the cyclic portion of the heterocycliccompound. In this definition, the term “heterocyclic compounds” refersto compounds derived from non-aromatic, monocyclic and polycycliccompounds having a ring structure composed of atoms of at least twodifferent elements. These heterocyclic compounds can also comprise oneor more double bonds.

As used herein, the term “substituted heterocyclyl groups” refers tounivalent functional groups derived from substituted heterocycliccompounds by removal of a hydrogen atom from an atom in the cyclicportion of the compound. In this definition, the term “substitutedheterocyclic compounds” refers to compounds derived from non-aromatic,monocyclic and polycyclic compounds having a ring structure composed ofatoms of at least two different elements where one or more of thehydrogen atoms of the cyclic compound is replaced with a non-hydrogenatom (e.g., a halogen atom) or a functional group (e.g., hydroxy group,alkyl group, aryl group, heteroaryl group). These substitutedheterocyclic compounds can also comprise one or more double bonds.

As used herein, the term “substituted aryl groups” refers to univalentfunctional groups derived from substituted arenes by removal of ahydrogen atom from a ring carbon atom. In this definition, the term“substituted arenes” refers to compounds derived from monocyclic andpolycyclic aromatic hydrocarbons in which one or more of the hydrogenatoms of the hydrocarbon is replaced with a non-hydrogen atom (e.g., ahalogen atom) or a non-alkyl functional group (e.g., hydroxy group).

As used herein, the term “substituted heteroaryl groups” refers tounivalent functional groups derived from substituted heteroarenes byremoval of a hydrogen atom from a ring carbon atom. In this definition,the term “substituted arenes” refers to compounds derived frommonocyclic and polycyclic aromatic hydrocarbons in which (1) one or moreof the hydrogen atoms of the hydrocarbon is replaced with a non-hydrogenatom (e.g., a halogen atom) or a non-alkyl functional group (e.g.,hydroxy group) and (2) at least one methine group (—C═) of thehydrocarbon is replaced by a trivalent heteroatom and/or at least onevinylidene group (—CH═CH—) of the hydrocarbon is replaced by a divalentheteroatom.

As used herein, the term “alkanediyl groups” refers to divalentfunctional groups derived from alkanes by removal of two hydrogen atomsfrom the alkane. These hydrogen atoms can be removed from the samecarbon atom on the alkane (as in ethane-1,1-diyl) or from differentcarbon atoms (as in ethane-1,2-diyl).

As used herein, the term “substituted alkanediyl groups” refers todivalent functional groups derived from substituted alkanes by removalof two hydrogen atoms from the alkane. These hydrogen atoms can beremoved from the same carbon atom on the substituted alkane (as in2-fluoroethane-1,1-diyl) or from different carbon atoms (as in1-fluoroethane-1,2-diyl). In this definition, the term “substitutedalkanes” has the same meaning as set forth above in the definition ofsubstituted alkyl groups.

As used herein, the term “alkenediyl groups” refers to divalentfunctional groups derived from acyclic, unbranched and branched olefins(i.e., hydrocarbons having one or more carbon-carbon double bonds) byremoval of two hydrogen atoms from the olefin. These hydrogen atoms canbe removed from the same carbon atom on the olefin (as inbut-2-ene-1,1-diyl) or from different carbon atoms (as inbut-2-ene-1,4-diyl).

As used herein, the term “acyl groups” refers to univalent functionalgroups derived from alkyl carboxylic acids by removal of a hydroxy groupfrom a carboxylic acid group. In this definition, the term “alkylcarboxylic acids” refers to acyclic, unbranched and branchedhydrocarbons having one or more carboxylic acid groups.

As used herein, the term “substituted acyl groups” refers to univalentfunctional groups derived from substituted alkyl carboxylic acids byremoval of a hydroxy group from a carboxylic acid group. In thisdefinition, the term “substituted alkyl carboxylic acids” refers tocompounds having one or more carboxylic acid groups bonded to asubstituted alkane, and the term “substituted alkane” is defined as itis above in the definition of substituted alkyl groups.

In a first embodiment, the invention provides a siloxane compoundcomprising a plurality of siloxane repeating units. Preferably, at leastsome of the siloxane repeating units are cyclotrisiloxane repeatingunits, and these cyclotrisiloxane repeating units are independentlyselected from the group consisting of repeating units conforming to thestructure of Formula (I) below:

In the structure of Formula (I), R₁ and R₂ are independently selectedfrom the group consisting of alkyl groups, substituted alkyl groups,cycloalkyl groups, substituted cycloalkyl groups, alkenyl groups,substituted alkenyl groups, cycloalkenyl groups, substitutedcycloalkenyl groups, heterocyclyl groups, substituted heterocyclylgroups, aryl groups, substituted aryl groups, heteroaryl groups,substituted heteroaryl groups, trialkylsiloxy groups, aryldialkylsiloxygroups, alkyldiarylsiloxy groups, and triarylsiloxy groups. R₃ and R₄are independently selected from the group consisting of alkyl groups,substituted alkyl groups, alkanediyl groups, substituted alkanediylgroups, cycloalkyl groups, substituted cycloalkyl groups, alkenylgroups, substituted alkenyl groups, alkenediyl groups, substitutedalkenediyl groups, cycloalkenyl groups, substituted cycloalkenyl groups,heterocyclyl groups, substituted heterocyclyl groups, aryl groups,substituted aryl groups, heteroaryl groups, substituted heteroarylgroups, trialkylsiloxy groups, aryldialkylsiloxy groups,alkyldiarylsiloxy groups, and triarylsiloxy groups. R₃ and R₄ can alsobe bonded together to form a cyclic moiety. Thus, if one of R₃ and R₄ isselected from the group consisting of alkanediyl groups, substitutedalkanediyl groups, alkenediyl groups, and substituted alkenediyl groups,then the other of R₃ and R₄ is also selected from the group consistingof alkanediyl groups, substituted alkanediyl groups, alkenediyl groups,and substituted alkenediyl groups, and R₃ and R₄ are bonded to form acyclic moiety. R₃ and R₄ can also be bonded together to form a cyclicmoiety. In the structure of Formula (I) and the structures that follow,the partial bonds (i.e., the bonds truncated by the wavy line) representbonds to adjacent moieties or repeating units.

In a preferred embodiment, R₁ and R₂ are independently selected from thegroup consisting of C₁-C₃₀ alkyl groups (e.g., C₁-C₈ alkyl groups),C₂-C₃₀ alkenyl groups (e.g., C₂-C₈ alkenyl groups), C₁-C₃₀ haloalkylgroups (e.g., C₁-C₈ haloalkyl groups), C₆-C₃₀ aryl groups (e.g., C₆-C₁₀aryl groups), C₇-C₃₁ aralkyl groups, C₃-C₉ trialkylsiloxy groups, C₈-C₂₆aryldialkylsiloxy groups, C₁₃-C₂₈ alkyldiarylsiloxy groups, and C₁₈-C₃₀)triarylsiloxy groups. More preferably, R₁ and R₂ are independentlyselected from the group consisting of C₁-C₈ alkyl groups, C₁-C₈haloalkyl groups, C₆-C₁₀ aryl groups, and C₇-C₃₁ aralkyl groups. Mostpreferably, R₁ and R₂ are independently selected from the groupconsisting of C₁-C₈ alkyl groups (e.g., methyl groups).

In a preferred embodiment, R₃ and R₄ are independently selected from thegroup consisting of C₁-C₃₀ alkyl groups (e.g., C₁-C₈ alkyl groups),C₁-C₅ alkanediyl groups, C₂-C₃₀ alkenyl groups (e.g., C₂-C₈ alkenylgroups), C₂-C₅ alkenediyl groups, C₁-C₃₀ haloalkyl groups (e.g., C₁-C₈haloalkyl groups), C₆-C₃₀ aryl groups (e.g., C₆-C₁₀ aryl groups), C₇-C₃₁aralkyl groups, C₃-C₉ trialkylsiloxy groups, C₈-C₂₆ aryldialkylsiloxygroups, C₁₃-C₂₈ alkyldiarylsiloxy groups, and C₁₈-C₃₀ triarylsiloxygroups. More preferably, R₃ and R₄ are independently selected from thegroup consisting of C₁-C₈ alkyl groups, C₁-C₈ haloalkyl groups, C₆-C₁₀aryl groups, and C₇-C₃₁ aralkyl groups. More preferably, R₃ and R₄ areindependently selected from the group consisting of C₆-C₁₀ aryl groups.Most preferably, R₃ and R₄ are each phenyl groups.

The siloxane compound of this first embodiment can comprise any suitableamount of siloxane repeating units conforming to the structure ofFormula (I). Preferably, about 10 mol. % or more of the siloxanerepeating units in the compound conform to the structure of Formula (I).More preferably, about 15 mol. % or more, about 20 mol. % or more, about25 mol. % or more, about 30 mol. % or more, about 35 mol. % or more,about 40 mol. % or more, about 45 mol. % or more, about 50 mol. % ormore, about 55 mol. % or more, about 60 mol. % or more, about 65 mol. %or more, about 70 mol. % or more, about 75 mol. % or more, about 80 mol.% or more, about 85 mol. % or more, or about 90 mol. % or more of thesiloxane repeating units in the compound conform to the structure ofFormula (I).

The percentage of siloxane repeating units possessing the recitedstructure can be determined by any suitable analytical technique. Forexample, the relative amount of silicon atoms in a particular repeatingunit can be quantified using ²⁹Si nuclear magnetic resonance (NMR). Thechemical shift of a silicon atom varies depending upon the particularmoiety or repeating unit within which the silicon atom resides. Thus,using the NMR spectrum of the siloxane compound, one can determine thedifferent types of silicon-containing moieties or repeating unitspresent in the compound. Furthermore, when the area under each peak inthe NMR spectrum is calculated, these area figures can be used todetermine the relative amount of silicon atoms present in each differenttype of siloxane moiety or repeating unit.

The cyclotrisiloxane repeating units present in the siloxane compound ofthis first embodiment possess the same basic structure (i.e., astructure conforming to Formula (I)), but all of the repeating units arenot necessarily substituted with the same groups. In other words, asiloxane compound according to this first embodiment of the inventioncan contain cyclotrisiloxane repeating units that differ in theselection of the R₁, R₂, R₃, and R₄ substituents.

As noted above, the siloxane compound of this first embodiment cancomprise siloxane units in addition to those conforming to the structureof Formula (I). For example, in a preferred embodiment, the siloxanecompound can comprise one or more segments conforming to the structureof Formula (X) below:

In the structure of Formula (X), R₁₀ and R₁₁ are independently selectedfrom the group consisting of hydrogen, alkyl groups, substituted alkylgroups, cycloalkyl groups, substituted cycloalkyl groups, alkenylgroups, substituted alkenyl groups, cycloalkenyl groups, substitutedcycloalkenyl groups, heterocyclyl groups, substituted heterocyclylgroups, aryl groups, substituted aryl groups, heteroaryl groups,substituted heteroaryl groups, trialkylsiloxy groups, aryldialkylsiloxygroups, alkyldiarylsiloxy groups, and triarylsiloxy groups. In thestructure of Formula (X), only one of R₁₀ and R₁₁ can be hydrogen. Morepreferably, R₁₀ and R₁₁ are independently selected from the groupconsisting of C₁-C₃₀ alkyl groups (e.g., C₁-C₈ alkyl groups), C₂-C₃₀alkenyl groups (e.g., C₂-C₈ alkenyl groups), C₁-C₃₀ haloalkyl groups(e.g., C₁-C₈ haloalkyl groups), C₆-C₃₀ aryl groups (e.g., C₆-C₁₀ arylgroups), C₇-C₃₁ aralkyl groups, C₃-C₉ trialkylsiloxy groups, C₈-C₂₆aryldialkylsiloxy groups, C₁₃-C₂₈ alkyldiarylsiloxy groups, and C₁₈-C₃₀)triarylsiloxy groups. More preferably, R₁₀ and R₁₁ are independentlyselected from the group consisting of C₁-C₈ alkyl groups, C₁-C₈haloalkyl groups, C₆-C₁₀ aryl groups, and C₇-C₃₁ aralkyl groups. Mostpreferably, R₁₀ and R₁₁ are independently selected from the groupconsisting of C₁-C₈ alkyl groups (e.g., methyl groups).

In another preferred embodiment, the siloxane compound of the firstembodiment further comprises at least one segment conforming to thestructure of Formula (XV) or Formula (XL) described below. The structureof Formula (XV) is

In this structure, R₁, R₃, and R₄ are selected from the groups describedabove. The structure of Formula (XL) is

In the structure of Formula (XL), R₁, R₂, R₃ and R₄ are selected fromthe groups described above, and R₂₀ and R₂₁ are independently selectedfrom the group consisting of hydrogen, alkyl groups, substituted alkylgroups, alkanediyl groups, substituted alkanediyl groups, cycloalkylgroups, substituted cycloalkyl groups, alkenyl groups, substitutedalkenyl groups, alkenediyl groups, substituted alkenediyl groups,cycloalkenyl groups, substituted cycloalkenyl groups, heterocyclylgroups, substituted heterocyclyl groups, aryl groups, substituted arylgroups, heteroaryl groups, substituted heteroaryl groups, trialkylsiloxygroups, aryldialkylsiloxy groups, alkyldiarylsiloxy groups, andtriarylsiloxy groups. In the structure of (XL), only one of R₂₀ and R₂₁can be hydrogen. Further, if one of R₂₀ and R₂₁ is selected from thegroup consisting of alkanediyl groups, substituted alkanediyl groups,alkenediyl groups, and substituted alkenediyl groups, then the other ofR₂₀ and R₂₁ is also selected from the group consisting of alkanediylgroups, substituted alkanediyl groups, alkenediyl groups, andsubstituted alkenediyl groups, and R₂₀ and R₂₁ are bonded to form acyclic moiety. The variable x is 0 or any positive integer; y is apositive integer from 1 to 6; and the sum of x and y is 2 or greater. Ina preferred embodiment, x is selected from the group consisting of 0, 1,and 2; y is a positive integer from 1 to 6; and the sum of x and y is aninteger from 2 to 8. In a more preferred embodiment, x is 1, and y is 1.

In a preferred embodiment of the structure of Formula (XL), R₂₀ isselected from the group consisting of C₁-C₃₀ alkyl groups (e.g., C₁-C₈alkyl groups), C₂-C₃₀ alkenyl groups (e.g., C₂-C₈ alkenyl groups),C₁-C₃₀ haloalkyl groups (e.g., C₁-C₈ haloalkyl groups), C₆-C₃₀ arylgroups (e.g., C₆-C₁₀ aryl groups), C₇-C₃₁ aralkyl groups, C₃-C₈trialkylsiloxy groups, C₈-C₂₆ aryldialkylsiloxy groups, C₁₃-C₂₈alkyldiarylsiloxy groups, and C₁₈-C₃₀) triarylsiloxy groups. Morepreferably, R₂₀ is selected from the group consisting of C₁-C₈ alkylgroups, C₁-C₈ haloalkyl groups, C₆-C₁₀ aryl groups, and C₇-C₃₁ aralkylgroups. In one particularly preferred embodiment, R₂₀ is selected fromthe group consisting of C₁-C₈ alkyl groups (e.g., a methyl group). Inanother particularly preferred embodiment, at least one of R₂₀ and R₂₁is selected from the group consisting of C₆-C₃₀ aryl groups (e.g.,C₆-C₁₀ aryl groups) and C₇-C₃₁ aralkyl groups, with a C₆-C₁₀ aryl groupbeing more preferred and a phenyl group being most preferred.

In another preferred embodiment, R₂₁ is selected from the groupconsisting of hydrogen, C₁-C₃₀ alkyl groups (e.g., C₁-C₈ alkyl groups),C₂-C₃₀ alkenyl groups (e.g., C₂-C₈ alkenyl groups), C₁-C₃₀ haloalkylgroups (e.g., C₁-C₈ haloalkyl groups), C₆-C₃₀ aryl groups (e.g., C₆-C₁₀aryl groups), C₇-C₃₁ aralkyl groups, C₃-C₉ trialkylsiloxy groups, C₈-C₂₆aryldialkylsiloxy groups, C₁₃-C₂₈ alkyldiarylsiloxy groups, and C₁₈-C₃₀)triarylsiloxy groups. More preferably, R₂₁ is selected from the groupconsisting of hydrogen, C₁-C₈ alkyl groups, C₁-C₈ haloalkyl groups,C₆-C₁₀ aryl groups, and C₇-C₃₁ aralkyl groups. Most preferably, R₂₁ isselected from the group consisting of C₁-C₈ alkyl groups (e.g., a methylgroup).

The structures drawn above only represent repeating units within thesiloxane compound. The siloxane compound further comprises terminatinggroups. These terminating groups can be any suitable terminating groupfor a siloxane compound. In a preferred embodiment, the siloxanecompound further comprises silyl terminating groups. Suitable silylterminating groups include, but are not limited to, trialkylsilylgroups, such as trimethylsilyl groups.

In another preferred embodiment, the siloxane compound can comprise oneor more cyclosiloxane terminating groups. Preferably, the cyclosiloxaneterminating group(s) conform to a structure selected from the groupconsisting of Formula (XLV) and Formula (XLVI)

In the structures of Formula (XLV) and Formula (XLVI), R₁, R₂, R₃, R₄,R₂₀, and R₂₁ are selected from the groups described above, and R₄₀ isselected from the group consisting of alkyl groups, substituted alkylgroups, cycloalkyl groups, substituted cycloalkyl groups, alkenylgroups, substituted alkenyl groups, cycloalkenyl groups, substitutedcycloalkenyl groups, heterocyclyl groups, substituted heterocyclylgroups, aryl groups, substituted aryl groups, heteroaryl groups,substituted heteroaryl groups. The variable x is 0 or any positiveinteger; and y is a positive integer from 1 to 6. In a preferredembodiment, x is selected from the group consisting of 0, 1, and 2; y isa positive integer from 1 to 6; and the sum of x and y is an integerfrom 1 to 8. In a particularly preferred embodiment of such acyclosiloxane terminating group, x is 0 and y is 1.

In a preferred embodiment, R₄₀ is selected from the group consisting ofC₁-C₃₀ alkyl groups (e.g., C₁-C₈ alkyl groups), C₂-C₃₀ alkenyl groups(e.g., C₂-C₈ alkenyl groups), C₁-C₃₀ haloalkyl groups (e.g., C₁-C₈haloalkyl groups), C₆-C₃₀ aryl groups (e.g., C₆-C₁₀ aryl groups), C₇-C₃₁aralkyl groups, C₃-C₉ trialkylsiloxy groups, C₈-C₂₆ aryldialkylsiloxygroups, C₁₃-C₂₈ alkyldiarylsiloxy groups, and C₁₈-C₃₀) triarylsiloxygroups. More preferably, R₄₀ is selected from the group consisting ofC₁-C₈ alkyl groups, C₁-C₈ haloalkyl groups, C₆-C₁₀ aryl groups, andC₇-C₃₁ aralkyl groups. Most preferably, R₄₀ is independently selectedfrom the group consisting of C₁-C₈ alkyl groups (e.g., methyl groups).

The siloxane compound of the first embodiment can have any suitablemolecular weight. Preferably, the siloxane compound has a molecularweight of about 500 mol/g or more. In a preferred embodiment, thesiloxane compound has molecular weight of about 500,000 mol/g or less.

The siloxane compound of the first embodiment preferably is opticallytransparent in at least the visible spectrum. The siloxane compound alsopreferably exhibits good stability (e.g., good thermal stability) andgood solubility in a variety of organic solvents, such as toluene,xylene, tetrahydrofuran, dichloromethane, and acetonitrile.

The siloxane compound of this first embodiment can be produced by anysuitable process. For example, the siloxane compound can be produced bydehydrogenative coupling of a hydrosilane and a hydroxysilane in thepresence of a suitable catalyst, such as a platinum or rutheniumcatalyst. However, in a second embodiment, the invention provides aprocess for producing siloxane compounds containing cyclosiloxanerepeating units, such as the siloxane compound of the first embodiment.In particular, the process comprises the steps of: (a) providing a firstsiloxane compound; (b) providing an organosilicon compound; (c)providing a reaction phase comprising a Lewis acid catalyst and asolvent; and (d) combining the first siloxane compound and theorganosilicon compound in the reaction phase under conditions so thatthe first siloxane compound and the organosilicon compound react in acondensation reaction to produce a second siloxane compound.

The first siloxane compound used in the process preferably comprises atleast one segment conforming to the structure of Formula (XX)

In the structure of Formula (XX), R₁, R₂, R₂₀, and R₂₁ are selected fromthe various groups described above.

The first siloxane compound used in the process can comprise anysuitable terminating groups. For example, the first siloxane compoundcan comprise silyl terminating groups, such as those discussed above inconnection with the siloxane compound of the first embodiment of theinvention. The first siloxane compound can also comprise hydride-bearingterminating groups. If such hydride-bearing terminating groups arepresent in the first siloxane compound, the siloxane compound producedby the process will contain some cyclosiloxane terminating groups, suchas the cyclosiloxane terminating groups conforming to Formula (XLV) andFormula (XLVI) described above.

The organosilicon compound used in the process preferably conforms tothe structure of Formula (XXX)

In the structure of (XXX), R₃ and R₄ are selected from the variousgroups described above, and R₃₀ and R₃₁ are independently selected fromthe group consisting of hydrogen, alkyl groups, substituted alkylgroups, acyl groups, and substituted acyl groups. Preferably, R₃₀ andR₃₁ are independently selected from the group consisting of hydrogen,C₁-C₃₃ alkyl groups (e.g., C₁-C₈ alkyl groups or C₁-C₄ alkyl groups),and C₁-C₃₀ acyl groups (e.g., C₁-C₈ acyl groups). Most preferably, R₃₀and R₃₁ are each hydrogen. The variable y is a positive integer,preferably a positive integer from 1 to 6, and most preferably y is 1.

The first siloxane compound and the organosilicon compound are combinedin a reaction phase comprising a Lewis acid catalyst and a solvent. Thereaction phase can comprise any inert solvent that does not promotereaction other than condensation of the SiH functionality of the firstsiloxane compound with the SiOR functionality of the organosiliconcompound, including undesired side reactions of these functionalities orof the siloxane bonds. Solvents comprising hydroxyl groups generally areinappropriate as solvents for the reaction phase. Depending on theidentity of the substituents on the first siloxane compound and theorganosilicon compound, the desired solvent can vary. Solvents that canbe employed independently or as a mixture include, but are not limitedto, aliphatic hydrocarbons (e.g., cyclohexane, heptane, or isooctane),aromatic hydrocarbons (e.g., toluene or xylenes), and siloxanes (e.g.,hexamethyldisiloxane, octamethylcyclotetrasiloxane, or othercyclosiloxanes).

The reaction phase can comprise any suitable Lewis acid catalyst. In apreferred embodiment, the Lewis acid comprises a triphenylborane havingthe formula B(C₆H_(x)X_(5-x))₃, where x is 0 to 5 and X is independentlyF, OCF₃, SCF₃, R, or OR where R is H, C₁-C₂₂ alkyl or C₆-C₂₂ aryl. Othercatalysts that can be employed are those disclosed in Priou et al. U.S.Pat. No. 6,593,500 and Deforth et al. U.S. Patent ApplicationPublication No. 2003/0139287, which are incorporated herein byreference. The Lewis acid catalysts can be further modified to inhibitits miscibility in a non-reactive phase of the reaction mixture. Forexample, the Lewis acid catalyst can be attached to a resin where thereis little or no affinity of the unreactive phase for the surface of theresin.

The first siloxane compound and the organosilicon compound are combinedin the reaction phase so that they react in a condensation reaction toform a cyclosiloxane moiety conforming to the structure of Formula (XL)and yield the second siloxane compound. The formation of thecyclosiloxane moiety begins with a condensation reaction between an SiHfunctionality on the first siloxane compound with an SiOR functionalityon the organosilicon compound. The cyclosiloxane moiety is completedwhen a remaining SiOR functionality on the molecule resulting from thisinitial reaction undergoes a condensation reaction with another SiHfunctionality on the same molecule. As will be understood by thoseskilled in the art, the subsequent reaction required to create thecyclosiloxane moiety also competes with other reactions that will notlead to the formation of a cyclosiloxane moiety. For example, theremaining SiOR functionality on the molecule resulting from the initialreaction could also undergo a condensation reaction with an SiHfunctionality on another molecule of the first siloxane compound. Theresult of such an intermolecular reaction will be a linking moietyconforming to the structure of Formula (XV), where the partial bondclosest to the silicon atom bearing the R₃ and R₄ groups represents abond to a silicon atom in a moiety derived from another molecule of thefirst siloxane compound. Thus, the reaction should be performed underconditions that are designed to promote the cyclo-condensation reactionover other competing intermolecular reactions. This can generally beaccomplished by using a quasi-dilute system. A quasi-dilute system, asemployed herein, is one where the products and one or more reagents canbe in a high concentration in the reaction vessel, but in the reactionphase, the reactive functionalities are in sufficiently lowconcentrations—often very low concentrations depending on the desiredsize of the cyclosiloxane moiety and the nature of its substituents—thatthe second intramolecular reaction needed to form the cyclosiloxanemoiety is very rapid relative to any intermolecular reaction.

The reaction can be performed at any suitable temperature. The reactiontemperature can vary over a large range, from 0° C. or lower totemperatures in excess of 100° C. or even 200° C., depending upon thereagents, catalysts and solvents used, as can be appreciated and readilydetermined by one skilled in the art.

Once the reaction is complete, the catalyst preferably is removed fromthe product or deactivated in order to stabilize the product. It isbelieved that residual “active” catalyst in the product may cause thecyclosiloxane rings to open and begin to form cross-links in the productas described below. The catalyst can be removed from the product byadsorbing the catalyst on a suitable adsorbent, such as aluminum oxide,and then filtering the product to remove the adsorbent. The catalyst canbe deactivated by adding any suitable Lewis base, such as an amine,phosphine, or phosphite, to the product.

In a third embodiment, the invention provides a siloxane compoundcomprising a plurality of siloxane repeating units. Preferably, at leasta portion of the siloxane repeating units are cyclosiloxane repeatingunits, and the cyclosiloxane repeating units are independently selectedfrom the group consisting of cyclosiloxane repeating units conforming tothe structure of Formula (XL) below

In the structure of Formula (XL), R₁, R₂, R₂₀, and R₂₁ are selected fromthe groups described above for the first embodiment of the invention.The variable x is 0 or any positive integer; and y is a positive integerfrom 1 to 6. In a preferred embodiment, x is selected from the groupconsisting of 0, 1, and 2; y is a positive integer from 1 to 6; and thesum of x and y is an integer from 1 to 8. In a particularly preferredembodiment, at least a portion of the repeating units have a structurein which x is 0 and y is 1. In the structure of Formula (XL), R₃ and R₄are independently selected from the group consisting of haloalkylgroups, aralkyl groups, aryl groups, substituted aryl groups, heteroarylgroups, and substituted heteroaryl groups. In a preferred embodiment, R₃and R₄ are independently selected from the group consisting of C₁-C₃₀haloalkyl groups (e.g., C₁-C₈ haloalkyl groups), C₇-C₃₁ aralkyl groups,C₆-C₃₀ aryl groups (e.g., C₆-C₁₀ aryl groups), and C₆-C₃₀ substitutedaryl groups (e.g., C₆-C₁₀ substituted aryl groups). More preferably, R₃and R₄ are independently selected from the group consisting of C₁-C₈haloalkyl groups, C₆-C₁₀ aryl groups, and C₆-C₁₀ substituted arylgroups. In one preferred embodiment, R₃ and R₄ are independentlyselected from the group consisting of C₆-C₁₀ aryl groups, with phenylgroups being particularly preferred. In another preferred embodiment, R₃and R₄ are independently selected from the group consisting of haloalkylgroups (e.g., C₁-C₈ haloalkyl groups), with fluoroalkyl groups (e.g.,C₁-C₈ fluoroalkyl groups) being particularly preferred.

As with the siloxane compound of the first embodiment, the siloxanecompound of this third embodiment can further comprise one or moresegments conforming to the structure of Formula (X) described above. Thesiloxane compound of this third embodiment can also comprise one or moresegments conforming to the structure of Formula (XV) described above.The siloxane compound can also comprise any suitable terminating groups,such as the various terminating groups described above in connectionwith the first embodiment of the invention.

The siloxane compound of this third embodiment can be produced by anysuitable process, including the process described above in connectionwith the second embodiment of the invention.

In a fourth embodiment, the invention provides a siloxane compoundconforming to the structure of Formula (LXX) below

In the structure of Formula (LXX), R₇₀ and R₇₁ are independentlyselected from the group consisting of haloalkyl groups, aralkyl groups,aryl groups, substituted aryl groups, heteroaryl groups, and substitutedheteroaryl groups. The variable c is 0 or a positive integer from 1 to3. R₇₂, R₇₃, R₇₄, R₇₅, R₇₆, R₇₇, R₇₈, R₈₀, R₈₁, R₈₂, R₈₃, R₈₄, R₈₅, andR₈₆ are independently selected from the group consisting of alkylgroups, substituted alkyl groups, cycloalkyl groups, substitutedcycloalkyl groups, alkenyl groups, substituted alkenyl groups,cycloalkenyl groups, substituted cycloalkenyl groups, heterocyclylgroups, substituted heterocyclyl groups, aryl groups, substituted arylgroups, heteroaryl groups, substituted heteroaryl groups, trialkylsiloxygroups, aryldialkylsiloxy groups, alkyldiarylsiloxy groups, andtriarylsiloxy groups. If c is 0, then R₇₄ and R₈₂ are independentlyselected from the group consisting of haloalkyl groups, aralkyl groups,aryl groups, substituted aryl groups, heteroaryl groups, and substitutedheteroaryl groups.

In a preferred embodiment, R₇₀ and R₇₁ are independently selected fromthe group consisting of C₁-C₃₀ haloalkyl groups (e.g., C₁-C₈ haloalkylgroups), C₇-C₃₁ aralkyl groups, C₆-C₃₀ aryl groups (e.g., C₆-C₁₀ arylgroups), and C₆-C₃₀ substituted aryl groups (e.g., C₆-C₁₀ substitutedaryl groups). More preferably, R₇₀ and R₇₁ are independently selectedfrom the group consisting of C₁-C₈ haloalkyl groups, C₆-C₁₀ aryl groups,and C₆-C₁₀ substituted aryl groups. In one preferred embodiment, R₇₀ andR₇₁ are independently selected from the group consisting of C₆-C₁₀ arylgroups, with phenyl groups being particularly preferred. In anotherpreferred embodiment, R₇₀ and R₇₁ are independently selected from thegroup consisting of haloalkyl groups (e.g., C₁-C₈ haloalkyl groups),with fluoroalkyl groups (e.g., C₁-C₈ fluoroalkyl groups) beingparticularly preferred.

In a preferred embodiment, R₇₂, R₇₃, R₇₄, R₇₅, R₇₆, R₇₇, R₇₈, R₈₀, R₈₁,R₈₂, R₈₃, R₈₄, R₈₅, and R₈₆ are independently selected from the groupconsisting of C₇-C₃₃ alkyl groups (e.g., C₁-C₈ alkyl groups), C₂-C₃₃alkenyl groups (e.g., C₂-C₈ alkenyl groups), C₁-C₃₃ haloalkyl groups(e.g., C₁-C₈ haloalkyl groups), C₆-C₃₃ aryl groups (e.g., C₆-C₁₀ arylgroups), C₇-C₃₁ aralkyl groups, C₃-C₉ trialkylsiloxy groups, C₈-C₂₆aryldialkylsiloxy groups, C₁₃-C₂₈ alkyldiarylsiloxy groups, and Cis-C₃₃triarylsiloxy groups. More preferably, R₇₂, R₇₃, R₇₄, R₇₅, R₇₆, R₇₇,R₇₈, R₈₀, R₈₁, R₈₂, R₈₃, R₈₄, R₈₅, and R₈₆ are independently selectedfrom the group consisting of alkyl groups (e.g., C₁-C₈ alkyl groups,haloalkyl groups (e.g., C₁-C₈ haloalkyl groups), aryl groups (e.g.,C₆-C₃₃ aryl groups), and aralkyl groups (e.g., C₇-C₃₁ aralkyl groups).Most preferably, R₇₂, R₇₃, R₇₅, R₇₆, R₇₇, R₇₈, R₈₀, R₈₁, R₈₃, R₈₄, R₈₅,and R₈₆ are independently selected from the group consisting of alkylgroups (e.g., C₁-C₈ alkyl groups, preferably methyl groups), and R₇₄ andR₈₂ are independently selected from the group consisting of aryl groups(e.g., C₆-C₃₃ aryl groups, C₆-C₁₀ aryl groups, preferably a phenylgroup).

In a preferred embodiment of a compound according to Formula (LXX) inwhich c is 0, R₇₂, R₇₃, R₇₅, R₇₆, R₇₇, R₇₈, R₈₀, R₈₁, R₈₃, R₈₄, R₈₅, andR₈₆ are independently selected from the group consisting of C₁-C₃₃ alkylgroups (e.g., C₁-C₈ alkyl groups), C₂-C₃₃ alkenyl groups (e.g., C₂-C₈alkenyl groups), C₁-C₃₃ haloalkyl groups (e.g., C₁-C₈ haloalkyl groups),C₆-C₃₃ aryl groups (e.g., C₆-C₁₀ aryl groups), C₇-C₃₁ aralkyl groups,C₃-C₉ trialkylsiloxy groups, C₈-C₂₆ aryldialkylsiloxy groups, C₁₃-C₂₈alkyldiarylsiloxy groups, and Cis-C₃₃ triarylsiloxy groups. Morepreferably, R₇₂, R₇₃, R₇₅, R₇₆, R₇₇, R₇₈, R₈₀, R₈₁, R₈₃, R₈₄, R₈₅, andR₈₆ are independently selected from the group consisting of alkyl groups(e.g., C₁-C₈ alkyl groups, haloalkyl groups (e.g., C₁-C₈ haloalkylgroups), aryl groups (e.g., C₆-C₃₃ aryl groups), and aralkyl groups(e.g., C₇-C₃₁ aralkyl groups). Most preferably, R₇₂, R₇₃, R₇₅, R₇₆, R₇₇,R₇₈, R₈₀, R₈₁, R₈₃, R₈₄, R₈₅, and R₈₆ are independently selected fromthe group consisting of alkyl groups (e.g., C₁-C₈ alkyl groups,preferably methyl groups). In such embodiments, R₇₄ and R₈₂ areindependently selected from the group consisting of C₁-C₃₀ haloalkylgroups (e.g., C₁-C₈ haloalkyl groups), C₇-C₃₁ aralkyl groups, C₆-C₃₀aryl groups (e.g., C₆-C₁₀ aryl groups), and C₆-C₃₀ substituted arylgroups (e.g., C₆-C₁₀ substituted aryl groups). More preferably, R₇₄ andR₈₂ are independently selected from the group consisting of C₁-C₈haloalkyl groups, C₆-C₁₀ aryl groups, and C₆-C₁₀ substituted arylgroups. In one preferred embodiment, R₇₄ and R₈₂ are independentlyselected from the group consisting of C₆-C₁₀ aryl groups, with phenylgroups being particularly preferred. In another preferred embodiment,R₇₄ and R₈₂ are independently selected from the group consisting ofhaloalkyl groups (e.g., C₁-C₈ haloalkyl groups), with fluoroalkyl groups(e.g., C₁-C₈ fluoroalkyl groups) being particularly preferred.

As noted above, the variable c is 0 or a positive integer from 1 to 3.In a particularly preferred embodiment, c is 1.

The siloxane compound conforming to the structure of Formula (LXX) canbe made by any suitable process. For example, the siloxane compound canbe produced by the process described above in the second embodiment ofthe invention using a different set of reactants. In particular, when cis a positive integer, the first siloxane compound used in such aprocess preferably conforms to the structure of Formula (LXXX) and theorganosilicon compound preferably conforms to the structure of Formula(XC). The structure of Formula (LXXX) is:

In the structure of Formula (LXXX), R₇₂, R₇₃, R₇₄, R₇₅, R₇₆, R₇₇, andR₇₈ are selected from the groups described above in connection with thestructure of Formula (LXX). The structure of Formula (XC) is:

In the structure of (XC), R₇₀ and R₇₁ are selected from the groupsdescribed above in connection with the structure of Formula (LXX). R₉₀and R₉₁ are independently selected from the group consisting ofhydrogen, alkyl groups, substituted alkyl groups, acyl groups, andsubstituted acyl groups. Preferably, R₉₀ and R₉₁ are independentlyselected from the group consisting of hydrogen, C₁-C₃₀ alkyl groups(e.g., C₁-C₈ alkyl groups or C₁-C₄ alkyl groups), and C₁-C₃₀ acyl groups(e.g., C₁-C₈ acyl groups). Most preferably, R₉₀ and R₉₁ are eachhydrogen. The variable c is a positive integer, preferably a positiveinteger from 1 to 3, and most preferably c is 1.

As will be understood by those skilled in the art, more than onesiloxane compound conforming to the structure of Formula (LXXX) can beused in the process of making the compound conforming to the structureof Formula (LXX). If more than one siloxane compound is used, theproduct of the process will comprise asymmetrical compounds in which theterminal cyclosiloxane groups have different substituents. Also, morethan one organosilicon compound conforming to the structure of Formula(XC) can be used in the process of making the compound conforming to thestructure of Formula (LXX). If more than one organosilicon compound isused, the product of the process will comprise asymmetrical compounds inwhich the terminal cyclosiloxane groups have different substituents. Ina preferred embodiment of the compound of Formula (LXX), the compound issymmetrical as would be produced by using only one siloxane compoundconforming to the structure of Formula (LXXX) and only one organosiliconcompound conforming to the structure of Formula (XC).

When c is 0 in the structure of Formula (LXX), the compound can beproduced by reacting a siloxane compound of Formula (CXX) with anorganosilicon compound of Formula (CX). The structure of Formula (CXX)is

In the structure of Formula (CXX), R₁₂₀ is selected from the groupsrecited above for R₇₄ and R₈₂ when c is 0 in Formula (LXX). Thestructure of Formula (CX) is

In the structure of Formula (CX), R₁₀₀, R₁₀₁, R₁₀₂, and R₁₀₃ areselected from the groups recited above for R₇₂, R₇₃, R₈₀, and R₈₁ when cis 0 in Formula (LXX).

The compounds of Formula (LXX) in which c is 0 can also be produced withmore than one siloxane compound conforming to the structure of Formula(CXX) and/or more than one organosilicon compound conforming to thestructure of Formula (CX). If more than one of either of the compoundsis used, the product of the process will comprise asymmetrical compoundsin which the terminal cyclosiloxane groups have different substituents.In a preferred embodiment of the compound of Formula (LXX) in which c is0, the compound is symmetrical as would be produced by using only onesiloxane compound conforming to the structure of Formula (CXX) and onlyone organosilicon compound conforming to the structure of Formula (CX).

The siloxane compounds of the first, third, and fourth embodimentsdescribed above are believed to be suited to a variety of applications.For example, with their cyclosiloxane moieties, these siloxane compoundsare believed to be well-suited for use in the production of cross-linkedsilicone polymers. In particular, it is believed the siloxane compoundsof the first and third embodiments can be used alone or in combinationwith other siloxane compounds, such as a siloxane compound conforming toFormula (LXX), and reacted with a suitable ring-opening catalyst thatwill open the cyclosiloxane moieties and form cross-links with othersiloxane compounds. The end result will be a cross-linked siliconepolymer. While not wishing to be bound to any particular theory, it isbelieved that the siloxane compounds of the invention will haveadvantages over other types of siloxane compounds used in the productionof cross-linked silicone polymers. For example, cross-linked siliconepolymers produced by conventional condensation cure mechanisms typicallyrelease volatile organic compounds (VOCs) as they cure. These VOCs are aby-product produced by the condensation reaction that results in theformation of new Si—O—Si linkages in the curing polymer. By way ofcontrast, the ring-opening and cross-linking mechanism of the inventivesiloxane compounds do not produce such VOCs as by-products. Further,this ring-opening curing mechanism can be initiated and propagated usingrelatively inexpensive materials. This stands in contrast to therelatively expensive platinum-based catalysts that are used inconventional hydrosilylation-cured cross-linked silicone polymersystems.

Thus, in a fifth embodiment, the invention provides a process forproducing a cross-linked silicone polymer and a cross-linked siliconepolymer produced by the process. The process generally comprises thesteps of (a) providing a first siloxane compound, (b) providing aring-opening catalyst, (c) combining the first siloxane compound and thering-opening catalyst to produce a reaction mixture; and (d) reactingthe components in the reaction mixture.

In this fifth embodiment, the first siloxane compound comprises aplurality of siloxane repeating units. Preferably, at least a portion ofthe siloxane repeating units are cyclosiloxane repeating units, and thecyclosiloxane repeating units are independently selected from the groupconsisting of cyclosiloxane repeating units conforming to the structureof Formula (XL)

In this embodiment, in the structure of Formula (XL), R₁, R₂, R₃, R₄,R₂₀, and R₂₁ are selected from the groups described above in connectionwith the siloxane compound of the first embodiment. The variable x is 0or any positive integer; and y is a positive integer from 1 to 6. In apreferred embodiment, x is selected from the group consisting of 0, 1,and 2; y is a positive integer from 1 to 6; and the sum of x and y is aninteger from 1 to 8. In a particularly preferred embodiment, at least aportion of the cyclosiloxane repeating units have a structure in which xis 0 and y is 1, which yields cyclosiloxane repeating units having astructure conforming to the structure of Formula (I). In such anembodiment, R₁, R₂, R₃, and R₄ can be selected from the groups describedabove in connection with Formula (I) in the siloxane compound of thefirst embodiment.

As with the siloxane compound of the first embodiment, the siloxanecompound used in the process of this fifth embodiment can furthercomprise one or more segments conforming to the structure of Formula (X)described above. The siloxane compound used in the process of this fifthembodiment can also comprise one or more segments conforming to thestructure of Formula (XV) described above. The siloxane compound canalso comprise any suitable terminating groups, such as the variousterminating groups described above in connection with the firstembodiment of the invention.

As can be drawn from the foregoing discussion, siloxane compoundssuitable for use in the process of this fifth embodiment include, butare not limited to, the siloxane compounds described above in connectionwith the first and third embodiments of the invention.

The process of this fifth embodiment of the invention uses aring-opening catalyst to create the cross-linked silicone polymer. Thering opening catalyst can be any suitable compound that is capable ofcatalyzing the opening of the cyclosiloxane moieties on the firstsiloxane compound used in the process. Suitable catalysts are described,for example, in Chapter 1 of the book Silicon-Containing Polymers: TheScience and Technology of Their Synthesis and Applications (James etal., Dordrecht: Kluwer Academic Publishers, 2000), in Chapter 3 of thebook Handbook of Ring-Opening Polymerization (Dubois et al., Weinheim:WILEY-VCH Verlag GmbH & Co. KGaA, 2009), in U.S. Patent ApplicationPublication No. 2008/0097064 A1 (Blanc-Magnard et al.), byJaroentomeechai et al. in Inorg. Chem. 2012, 51, 12266-72, and byGilbert et al. in Journal of Polymer Science 1959, XL, 35-58. Onesuitable class of ring-opening catalysts is compounds comprising one ormore silanolate or siloxanolate moieties. In a preferred embodiment, thering opening catalyst can be selected from the group consisting ofsiloxanolate salts (eg., tetramethylammonium siloxanolate),diaralkylsilanolate salts (e.g., sodium dimethylphenylsilanolate), andphosphonium hydroxides (e.g., tetralakylphosphonium hydroxides).

In this process embodiment, the siloxane compound and the ring-openingcatalyst are combined to form a reaction mixture. The reaction mixturecan comprise other components in addition to the siloxane compound andthe ring-opening catalyst. For example, the reaction mixture cancomprise a suitable solvent or diluent. The reaction mixture can alsocomprise one or more additional siloxane compounds, including siloxanecompounds that are capable of participating in the curing reaction ofthe cross-linked silicone polymer. For example, in one embodiment, thereaction mixture can further comprise a compound conforming to astructure selected from the group consisting of Formula (LX), Formula(LXV), and Formula (LXX). The structure of Formula (LXX) is depictedabove and the substituents on the structure are selected from the groupsdescribed above. The structure of Formula (LX) is

In the structure of Formula (LX), R₆₀, R₆₁, R₆₂, and R₆₃ areindependently selected from the group consisting of alkyl groups,substituted alkyl groups, cycloalkyl groups, substituted cycloalkylgroups, alkenyl groups, substituted alkenyl groups, cycloalkenyl groups,substituted cycloalkenyl groups, heterocyclyl groups, substitutedheterocyclyl groups, aryl groups, substituted aryl groups, heteroarylgroups, substituted heteroaryl groups, trialkylsiloxy groups,aryldialkylsiloxy groups, alkyldiarylsiloxy groups, and triarylsiloxygroups. The variable a is a positive integer; b is a positive integer;and the sum of a and b is from 3 to 5. Preferably, the sum of a and b is3. Preferably, R₆₀, R₆₁, R₆₂, and R₆₃ are independently selected fromthe group consisting of C₁-C₃₀ alkyl groups (e.g., C₁-C₈ alkyl groups),C₂-C₃₀ alkenyl groups (e.g., C₂-C₈ alkenyl groups), C₁-C₃₀ haloalkylgroups (e.g., C₁-C₈ haloalkyl groups), C₆-C₃₀ aryl groups (e.g., C₆-C₁₀aryl groups), C₇-C₃₁ aralkyl groups, C₃-C₉ trialkylsiloxy groups, C₈-C₂₆aryldialkylsiloxy groups, C₁₃-C₂₈ alkyldiarylsiloxy groups, and C₁₈-C₃₀triarylsiloxy groups. More preferably, R₆₀, R₆₁, R₆₂, and R₆₃ areindependently selected from the group consisting of C₁-C₈ alkyl groups,C₁-C₈ haloalkyl groups, C₆-C₁₀ aryl groups, and C₇-C₃₁ aralkyl groups.In one specific preferred embodiment, R₆₀ and R₆₁ are selected form thegroup consisting of haloalkyl groups (e.g., C₁-C₃₀ haloalkyl groups,preferably C₁-C₈ haloalkyl groups), aryl groups (e.g., C₆-C₃₀ arylgroups, C₆-C₁₀ aryl groups), and aralkyl groups (e.g., C₇-C₃₁ aralkylgroups), with aryl groups being particularly preferred and phenyl groupsbeing most preferred. In another specific preferred embodiment, R₆₂ andR₆₃ are selected from the group consisting of alkyl groups (e.g., C₁-C₃₀alkyl groups, preferably C₁-C₈ alkyl groups), with methyl groups beingparticularly preferred.

The structure of Formula (LXV) is

In the structure of Formula (LXV), R₆₅ and R₆₈ are independentlyselected from the group consisting of hydrogen, alkyl groups,substituted alkyl groups, acyl groups, substituted acyl groups,trialkylsilyl groups, aryldialkylsilyl groups, alkyldiarylsilyl groups,and triarylsilyl groups. R₆₆ and R₆₇ are independently selected from thegroup consisting of alkyl groups, substituted alkyl groups, cycloalkylgroups, substituted cycloalkyl groups, alkenyl groups, substitutedalkenyl groups, cycloalkenyl groups, substituted cycloalkenyl groups,heterocyclyl groups, substituted heterocyclyl groups, aryl groups,substituted aryl groups, heteroaryl groups, substituted heteroarylgroups, trialkylsiloxy groups, aryldialkylsiloxy groups,alkyldiarylsiloxy groups, and triarylsiloxy groups. The variable n is apositive integer. Preferably, R₆₅ and R₆₈ are independently selectedfrom the group consisting of hydrogen, C₁-C₃₀ alkyl groups (e.g., C₁-C₈alkyl groups or C₁-C₄ alkyl groups), and C₁-C₃₀ acyl groups (e.g., C₁-C₈acyl groups). Most preferably, R₆₅ and R₆₈ are each hydrogen.Preferably, R₆₆ and R₆₇ are independently selected from the groupconsisting of C₁-C₃₀ alkyl groups (e.g., C₁-C₈ alkyl groups), C₂-C₃₀alkenyl groups (e.g., C₂-C₈ alkenyl groups), C₁-C₃₀ haloalkyl groups(e.g., C₁-C₈ haloalkyl groups), C₆-C₃₀ aryl groups (e.g., C₆-C₁₀ arylgroups), C₇-C₃₁ aralkyl groups, C₃-C₉ trialkylsiloxy groups, C₈-C₂₆aryldialkylsiloxy groups, C₁₃-C₂₈ alkyldiarylsiloxy groups, and C₁₈-C₃₀)triarylsiloxy groups. More preferably, R₆₆ and R₆₇ are independentlyselected from the group consisting of C₁-C₈ alkyl groups, C₁-C₈haloalkyl groups, C₆-C₁₀ aryl groups, and C₇-C₃₁ aralkyl groups.

As noted above, the ring-opening catalyst reacts with the siloxanecompound to open at least a portion of the cyclosiloxane repeatingunits. The resulting “opened” moiety (i.e., the “opened” formercyclosiloxane repeating unit) has a reactive group on its terminal endthat can form an Si—O—Si linkage by reacting with another silicon atom.Thus, when this opened moiety reacts to form an Si—O—Si linkage withanother molecule of the first siloxane compound, the result is across-link between formerly separate siloxane molecules. As this processrepeats multiple times, the end result is a cross-linked siliconepolymer. In order to accelerate this curing mechanism, the reactionmixture and cross-linked silicone polymer can be heated to an elevatedtemperature. Further, the reaction mixture preferably is degassed toavoid the formation of bubbles in the cross-linked silicone polymer. Thereaction mixture can be degassed using any suitable technique knownwithin the art.

The cross-linked silicone polymer of the invention preferably exhibits arelatively high degree of thermal stability as evinced by a lack of orvery low level of yellowing after exposure to elevated temperatures.More specifically, the cross-linked silicone polymer of the inventionpreferably exhibits no yellowing after exposure to a temperature of 200°C. for 1,000 hours. The cross-linked silicone polymer of the inventioncan be made to a variety of different hardnesses, depending upon theparticular conditions used in making the polymer. For example, thecross-linked silicone polymer can be a gel or can be a solid exhibitinga Shore D hardness. The cross-linked silicone polymer of the inventioncan also be made to exhibit a refractive index selected from a ratherwide range. The refractive index of the polymer will depend on thesubstituents on the siloxane compound used to produce the polymer. Inparticular, the cross-linked silicone polymer can exhibit a refractiveindex from about 1.35 to about 1.6. In a preferred embodiment, thecross-linked silicone polymer exhibits a refractive index of about 1.5or greater or about 1.55 or greater (e.g., about 1.57 or greater).

In a sixth embodiment, the invention provides a kit for producing across-linked silicone polymer. The kit comprises a first part and asecond part. The first part and the second part are physically isolatedfrom each other to prevent mixing of the components contained in eachpart. The first part comprises the first siloxane compound describedabove in connection with the process for producing the cross-linkedsilicone polymer, as well as any of the additional siloxane compoundsdisclosed above as being suitable for use in such process. The secondpart comprises the ring-opening catalyst. Thus, when the first part andthe second part are mixed, the siloxane compound and the ring-openingcatalyst react to form a cross-linked silicone polymer as describedabove.

The first and second parts of the kit can comprise other components. Forexample, the first part can also comprise one or more adhesionpromoters. The second part can comprise a siloxane fluid, which providesa medium in which the ring-opening catalyst can be dispersed. The firstor second part can also comprise a reactive or non-reactive diluent toadjust the viscosity of the system.

The kit can be provided in any suitable form. For example, the kit canbe provided in the form of two separate and distinct vessels whosecontents (or a portion thereof) are removed and manually mixed when theuser desires to make the cross-linked silicone polymer. Alternatively,the kit can be provided in the form of a tube having two separatechambers with each chamber holding one of the first part and the secondpart. Each chamber can have an outlet, and the two outlets can belocated proximate to each other. Thus, when the contents in the tube arecompressed, the contents of each part are expelled from their respectiveoutlets where they mix on the target surface. Alternatively, the twooutlets can feed into a nozzle that is designed to thoroughly mix thecontents of each part before they exit the nozzle.

The cross-linked silicone polymer described above is believed to besuited for use in a wide range of applications. Given the fact that theelastomer does not generate the VOCs typically produced by conventionalcondensation cure elastomers and the capability of tailoring theelastomers refractive index through the use of certain groups on thesiloxane starting materials (e.g., haloalkyl groups, aralkyl groups,aryl groups, substituted aryl groups, heteroaryl groups, or substitutedaryl groups), it is believed that the elastomer is particularly suitedfor use in electronics, such as an encapsulant for a light emittingdiode (LED). Further, it is believed that the lack of VOC generationalso tends to reduce shrinkage that occurs when the polymer cures(typically shrinkage is less than 5%, preferably less than 2%), makingthe polymer particularly well-suited for use as a sealant orencapsulant.

In a seventh embodiment, the invention provides an LED that utilizes across-linked silicone polymer according to the invention (e.g., across-linked silicone polymer produced by the above-described process orusing the above-described kit) as an encapsulant. FIG. 1 provides asimplified, schematic cross-sectional view of such an LED. The LED 100comprises (a) a semiconductor crystal 102, (b) a cathode 104electrically connected to the semiconductor crystal 102, (c) an anode106 electrically connected to the semiconductor crystal 102, and (d) anencapsulant material 110 surrounding the semiconductor crystal 102. Asnoted above, the encapsulant material 110 comprises a cross-linkedsilicone polymer according to the invention.

The semiconductor crystal can be composed of any crystallinesemiconductor material suitable for generating radiation (e.g., visiblelight) when a current is passed through the material. Suitablesemiconductor crystals are well-known within the art, with crystals madefrom gallium nitride being among those commonly used. Further, thesemiconductor crystal can be carried on any suitable support knownwithin the art, such as silicon carbide or sapphire. Basically, thesemiconductor crystal 102 comprises an n-type semiconductor material ina first region (not pictured) of the semiconductor crystal and a p-typesemiconductor material in a second region (not pictured) of thesemiconductor material. The boundary between the first region and thesecond region of the semiconductor material provides a p-n junction.

The LED 100 further comprises a cathode 104 electrically connected tothe first region of the semiconductor crystal 102. The cathode can beany suitable material (e.g., metal) that is capable of carrying theelectric current necessary to power the LED. As shown in FIG. 1, thesemiconductor crystal 102 can be directed attached to the cathode 104thereby providing the electrical connection to the first region.Alternatively, the cathode can be connected to the semiconductor crystalby a suitable bond wire, as discussed below in regards to the anode. Theanode 106 is electrically connected to the second region of thesemiconductor crystal 102. The anode can be any suitable material (e.g.,metal) that is capable of carrying the electric current necessary topower the LED. As shown in FIG. 1, the anode 106 can be electricallyconnected to the second region of the semiconductor crystal by asuitable bond wire 108. The bond wire can be any suitable material can(e.g., metal) that is capable of carrying the electric current from theanode to the second region of the semiconductor material.

As noted above, the LED 100 further comprises an encapsulant material110 surrounding the semiconductor crystal 102. As shown in FIG. 1, theencapsulant 110 can also surround the cathode 104 and anode 106 if thetwo are separate from the semiconductor crystal 102, but this is notnecessary. The encapsulant material provides two basic functions. First,it protects the semiconductor crystal and the electrical connections tothe crystal from damage by external forces or contaminants. Second, theencapsulant material provides a transition between the high refractiveindex material of the semiconductor crystal and the low refractive indexair surrounding the LED. As known by those familiar with the art, therelatively large difference between the refractive index of thesemiconductor crystal and the surrounding air leads to internalreflection of light within the LED. These internal reflections reducethe amount of light that escapes from the semiconductor crystal and isemitted by the LED. By providing a medium with an intermediaterefractive index (i.e., a refractive index between the high refractiveindex of the semiconductor crystal and the refractive index of air), theencapsulant material can reduce the amount of light that is internallyreflected back into the semiconductor crystal, thereby increasing theamount of light emitted by the LED.

As noted above, the encapsulant material preferably comprises across-linked silicone polymer according to the invention. In particular,the encapsulant material preferably comprises a cross-linked siliconepolymer in which at least a portion of the functional groups present onthe cross-linked silicone polymer are selected from the group consistingof haloalkyl groups, aralkyl groups, aryl groups, substituted arylgroups, heteroaryl groups, or substituted aryl groups, with haloalkylgroups, aryl groups, and aralkyl groups being particularly preferred.Processes for producing such cross-linked silicone polymers aredescribed above. It is believed that the presence of these groups yieldsa cross-linked silicone polymer having a higher refractive index thatwill provide an improved transition and lower the amount of internalreflections back into the LED.

The encapsulant material can comprise other components in addition tothe cross-linked silicone polymer of the invention. For example, theencapsulant material can further comprise phosphors, which convert someof the light generated by the semiconductor crystal to differentwavelengths in order to modify the wavelengths of light emitted by theLED. Any suitable phosphor or combination of phosphors can be used.Suitable phosphors are well known within the art.

As depicted in FIG. 1, the LED 100 can further comprise a cover or lens112 enclosing the internal components. The cover or lens can serve tofurther protect the internal components of the LED and can also serve tofocus the light generated by the LED.

The following examples further illustrate the subject matter describedabove but, of course, should not be construed as in any way limiting thescope thereof.

Example 1

This example demonstrates the preparation of a siloxane compoundaccording to the invention comprising cyclosiloxane repeating units.

54 g diphenylsilanediol (250 mmol), 200 mg tris(pentafluorophenyl)borane(0.391 mmol), and 1000 ml xylene were added at room temperature andunder argon to a three neck 2 L flask equipped with a magnetic stirringbar. With vigorous stirring, a mixture of 36.45 gα,ω-bis(trimethylsiloxy)polymethylhydrosiloxane (607.5 mmol [Si—H],average Mn=1700-3200) and 18 ml xylene was slowly added over 17 hoursusing a syringe pump at room temperature. Gas bubbles formed during theaddition. After addition, the solution was further stirred for 1 hour.Approximately 74 g neutral aluminum oxide was then added to thesolution, and the mixture was allowed to stand overnight. The solutionwas then filtered through a fritted filter. The solvent in the filtratewas then removed under high vacuum to give a sticky white product. Thesticky white product was then soaked in 200 ml ethanol for 12 hours atroom temperature. The ethanol was then removed under vacuum, and asticky gum was obtained. The gum was then dissolved in around 100 mldiethyl ether. The ether solution was then added to a stirring solutionof 400 ml hexamethyldisiloxane, and a precipitate formed duringaddition. The solution was then decanted, and the precipitate was driedunder vacuum to remove any residual solvent and give 85 g of product(˜94% yield). GPC (THF, room temperature, calibrated by polystyrene):Mn=5049, PD=29.3; NMR: ¹H NMR (ppm, CDCl₃) δ 7.65 (broad and multiplepeaks, 4H), 7.30 (broad and multiple peaks, 6H), 0.07 (broad andmultiple peaks, 6H) ³¹C NMR (ppm, CDCl₃) δ 134 (multiple peaks), 130(multiple peaks) 128 (multiple peaks) −3 (multiple peaks) ²⁹Si NMR (ppm,CDCl₃) δ 8.8 (O-TMS), −37.1 (multiple peaks, —O-SiPh₂-O— in D3 ring),−46 (multiple peaks, —O-SiPh₂-O— in non-D3 form), −56.9 (Me-SiO3- in D3ring), −66.1 (Me-SiO3- in non-D3 ring); IR: 2956, 1592, 1429, 1269,1227, 1122, 990, 906, 843, 773, 695.

Example 2

This example demonstrates the preparation of a siloxane compoundaccording to the invention comprising cyclosiloxane repeating units.

80 mg tris(pentafluorophenyl)borane (0.156 mmol) and 150 ml xylene wereadded under argon to a three neck flask equipped with a magneticstirring bar. The temperature of the solution was kept at 60° C. Withvigorous stirring, a mixture of 12 gα,ω-bis(trimethylsiloxy)polymethylhydrosiloxane (200 mmol [Si—H],average Mn=1700-3200), 22 g dimethoxydiphenylsilane (90 mmol) and 15 mlxylene was slowly added over 3 hours. Gas bubbles formed during theaddition. After addition, the reaction was kept going for another twohours at 60° C., and 0.5 hour at 120° C. The solution was then cooled toroom temperature, and 41 mg triphenylphosphine (0.156 mmol) was added.The solvent was then removed under vacuum to give around 30 g of ahighly viscous liquid (˜96% yield). There were around 6% (mol %) Si—Hand 5% (mol %) Si—OMe leftover in the product. Mn=4109, PD=14.4; ¹H NMR(ppm, CDCl₃) δ 7.60 (broad and multiple peaks, 4H), 7.25 (broad andmultiple peaks, 6H), 0.00 (broad and multiple peaks, 6H ²⁹Si NMR (ppm,CDCl₃) δ 10, −37, −47, −57, −67; IR 2969, 1429, 1269, 1121, 988, 904,846, 772, 695.

Example 3

This example demonstrates the preparation of a siloxane compoundaccording to the invention comprising cyclosiloxane repeating units.

80 mg tris(pentafluorophenyl)borane (0.156 mmol) and 150 ml xylene wereadded under argon to a three neck flask equipped with a magneticstirring bar. The temperature of the solution was kept at 60° C. Withvigorous stirring, a mixture of 12 gα,ω-bis(trimethylsiloxy)polymethylhydrosiloxane (200 mmol [Si—H],average Mn=1700-3200), 12 g dimethoxydimethylsilane (100 mmol) wasslowly added over 4 hours. Gas bubbles formed during the addition. Afteraddition, the reaction was held at 60° C. for another hour. The solutionwas then cooled down to room temperature, and 18 g Al₂O₃ was added. Themixture was left overnight. Then, the mixture was filtered and solventwas removed under vacuum to give approximately 20 g of a clear andsticky liquid (˜95% yield). There were around 6% (mol %) Si—H and 9%(mol %) Si—OMe leftover in the product. Mn=4249, PD=8.5; ¹H NMR (ppm,CDCl₃) δ 0.00 (broad, 12H); ²⁹Si NMR (ppm, CDCl₃) δ 8, −8, −11, −19,−21, −54, −58, −67; IR 2964, 1264, 1002, 907, 849, 760, 702.

Example 4

This example demonstrates the preparation of a siloxane compoundaccording to the invention comprising cyclosiloxane repeating units.

54.08 g diphenylsilanediol (250 mmol), 200 mgtris(pentafluorophenyl)borane (0.391 mmol), and 1000 ml xylene wereadded at room temperature and under argon to a three neck flask equippedwith a magnetic stirring bar. With vigorous stirring, 68.5 g of atrimethylsiloxyl-terminated methylhyrdrosiloxane-dimethylsiloxanecopolymer (500 mmol [Si—H], average Mn=680) was slowly added over 24hours using a syringe pump. Gas bubbles formed during the addition.After addition, the reaction temperature was raised to 60° C., andstirred for 4.5 hours. IR indicated no residual Si—H. Then, 78 g neutralaluminum oxide was added to the solution. After 1 hour, the solution wasfiltered, and the solvent in the filtrate was removed under high vacuumto give a sticky liquid (17.5 g, ˜96% yield). The refractive index ofthe product was 1.4965 @ 589.3 nm. Mn=3543, PD=1.9; ¹H NMR (ppm, CDCl₃)δ 7.60 (broad and multiple peaks, 4H), 7.30 (broad and multiple peaks,6H), 0.00 (broad and multiple peaks, 19H); ³¹C NMR (ppm, CDCl₃) δ 134(multiple peaks), 130 (multiple peaks), 127 (multiple peaks), 0,(multiple peaks), −3 (multiple peaks); ²⁹Si NMR (ppm, CDCl₃) δ 9, −20,−36, −47, −57, −66; IR 2962, 1429, 1262, 1006, 842, 792, 697.

Example 5

This example demonstrates the preparation of a siloxane compoundconforming to the structure of Formula (LXX).

50 ml xylene, 0.04 g tris(pentafluorophenyl)borane (0.078 mmol), and 5.4g diphenylsialnediol (25 mmol) were added under argon to a three neckflask equipped with a magnetic stirring bar. With vigorous stirring, amixture of 5.50 g phenyltris(dimethylsiloxy)silane (16.7 mmol) and 2.75g xylene was slowly added to the flask at 50° C. over 3 hours. Gasbubbles formed during the addition. After addition, the reaction mixturewas then heated at 50° C. until no Si—H was detected by IR (around 1hour). The reaction mixture was then cooled to room temperature, and 9 galuminium oxide was added. After sitting overnight at room temperature,the reaction mixture was filtered, and the solvent was removed underreduced pressure to yield a clear liquid (10.5 g, ˜95% yield). MALDI-TOFconfirmed the molecular weight ((M+K⁺) calculated: 1335, found: 1335).There were two adjacent peaks in GPC results, which indicated that thereare two isomers present. ¹H NMR (ppm, CDCl₃) δ 7.60 (multiple peaks,16H), 7.30 (multiple peaks, 24H), 0.08 (multiple peaks, 36H) ³¹C NMR(ppm, CDCl₃) δ 134 (multiple peaks), 130 (multiple peaks), 128 (multiplepeaks), 1 (multiple peaks) ²⁹Si NMR (ppm, CDCl₃) δ −17, −19, −46, −48,−79; IR 2962, 1429, 1259, 1009, 839, 797, 742, 695, 597.

Example 6

This example demonstrates the preparation of a cross-linked siliconepolymer according to the invention.

A 2 g THF solution of 0.2 g of a polycyclosiloxane according to theinvention and a 2.5 g THF solution of 0.6 g1,1-diphenyl-3,3,5,5-tetramethylcyclotrisiloxane were mixed. Then, 0.048mg tetramethylammonium siloxanolate (60 ppm, Gelest catalog SIT7502.0)in 0.196 g THF was added to the mixture. The solution was then shakenwell, and the solvent was removed under vacuum to give white solids. Thesolids were then heated at 75° C. for 2 hours, 125° C. for 18 hours and150° C. for 2 hours to fully cure. The resulting cross-linked siliconepolymer had a Shore A hardness of around 39 and a transparency of 97% at400 nm.

Example 7

This example demonstrates the preparation of different cross-linkedsilicone polymers according to the invention and the differentproperties exhibited by these polymers.

Four cross-linked silicone polymers (Samples 7A-7D) were prepared inaccordance with the general procedure outlined in Example 6, with theratio of the polycyclosiloxane compound and, if present,1,1-diphenyl-3,3,5,5-tetramethylcyclotrisiloxane being varied as setforth in Table 1. Table 1 also lists the hardness of the resultingpolymers.

TABLE 1 Reactants used to make and hardness of Samples 7A-7D. Weightratio polycyclosiloxane:1,1-diphenyl- Sample3,3,5,5-tetramethylcyclotrisiloxane Shore Hardness 7A 1:0 >100 (A)  7B  1:1.5 80 (A) 7C 1:3 30 (A) 7D 1:6 16 (A)

Example 8

This example demonstrates the preparation of a cross-linked siliconepolymer according to the invention.

0.5 g of the poly(cyclo)siloxane of Example 1 and 1.5 g phenylmethylcyclotetrasiloxanes were dissolved in THF. Then, 0.12 mgtetramethylammonium siloxanolate (60 ppm, Gelest catalog SIT7502.0) inTHF was added to the mixture. The solution was shaken well, and thesolvent was removed under vacuum to give a clear liquid. The liquid wasthen heated at 125° C. for 16 hours to cure into a soft elastomer. Theresulting elastomer had a Shore A hardness of around 20.

Example 9

This example demonstrates the preparation of a cross-linked siliconepolymer according to the invention.

0.05 g of the poly(cyclo)siloxane of Example 1 and 0.15 g phenylmethylcyclotetrasiloxanes (Gelest catalog no SIP6737-100g) were dissolved inTHF. Then, 0.012 mg sodium dimethylphenylsilanolate (60 ppm, SigmaAldrich, catalog no 673269-1G) in THF was added to the mixture. Thesolution was shaken well, and the solvent was removed under vacuum togive a clear liquid. The liquid was then heated at 75° C. for 40 minutesand 150° C. for 4 hours to cure into a soft elastomer.

Example 10

This example demonstrates the preparation of a cross-linked siliconepolymer according to the invention.

Two grams of the compound from Example 5 were dissolved in THF, and then1.2 mg tetramethylammonium siloxanolate (600 ppm, Gelest catalogSIT7502.0) was added to the solution. THF was then removed to give aclear liquid. The liquid was then heated at 75° C. for 1 hour and 120°C. for 5 hours to cure into a very soft elastomer. The catalyst was thenremoved by heating at 150° C. for 1 hour. The elastomer had a Shore Ahardness of approximately 0. In another experiment, 0.67 g of thepolycyclosiloxane of Example 1 and 1.33 g of the compound from Example 5were cured in a similar manner to give an elastomer with a Shore Ahardness of around 50.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the subject matter of this application (especiallyin the context of the following claims) are to be construed to coverboth the singular and the plural, unless otherwise indicated herein orclearly contradicted by context. The terms “comprising,” “having,”“including,” and “containing” are to be construed as open-ended terms(i.e., meaning “including, but not limited to,”) unless otherwise noted.Recitation of ranges of values herein are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein, and eachseparate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate the subject matter of theapplication and does not pose a limitation on the scope of the subjectmatter unless otherwise claimed. No language in the specification shouldbe construed as indicating any non-claimed element as essential to thepractice of the subject matter described herein.

Preferred embodiments of the subject matter of this application aredescribed herein, including the best mode known to the inventors forcarrying out the claimed subject matter. Variations of those preferredembodiments may become apparent to those of ordinary skill in the artupon reading the foregoing description. The inventors expect skilledartisans to employ such variations as appropriate, and the inventorsintend for the subject matter described herein to be practiced otherwisethan as specifically described herein. Accordingly, this disclosureincludes all modifications and equivalents of the subject matter recitedin the claims appended hereto as permitted by applicable law. Moreover,any combination of the above-described elements in all possiblevariations thereof is encompassed by the present disclosure unlessotherwise indicated herein or otherwise clearly contradicted by context.

What is claimed is:
 1. A compound conforming to the structure of Formula(LXX)

wherein R₇₀ and R₇₁ are independently selected from the group consistingof haloalkyl groups, aralkyl groups, aryl groups, substituted arylgroups, heteroaryl groups, and substituted heteroaryl groups; c is 0 ora positive integer from 1 to 3; R₇₂, R₇₃, R₇₄, R₇₅, R₇₆, R₇₇, R₇₈, R₈₀,R₈₁, R₈₂, R₈₃, R₈₄, R₈₅, and R₈₆ are independently selected from thegroup consisting of alkyl groups, substituted alkyl groups, cycloalkylgroups, substituted cycloalkyl groups, alkenyl groups, substitutedalkenyl groups, cycloalkenyl groups, substituted cycloalkenyl groups,heterocyclyl groups, substituted heterocyclyl groups, aryl groups,substituted aryl groups, heteroaryl groups, substituted heteroarylgroups, trialkylsiloxy groups, aryldialkylsiloxy groups,alkyldiarylsiloxy groups, and triarylsiloxy groups; provided, if c is 0,then R₇₄ and R₈₂ are independently selected from the group consisting ofhaloalkyl groups, aralkyl groups, aryl groups, substituted aryl groups,heteroaryl groups, and substituted heteroaryl groups.
 2. The compound ofclaim 1, wherein R₇₀ and R₇₁ are independently selected from the groupconsisting of aryl groups.
 3. The compound of claim 2, wherein R₇₀ andR₇₁ are each phenyl groups.
 4. The compound of claim 1, wherein R₇₂,R₇₃, R₇₄, R₇₅, R₇₆, R₇₇, R₇₈, R₈₀, R₈₁, R₈₂, R₈₃, R₈₄, R₈₅, and R₈₆ areindependently selected from the group consisting of alkyl groups andaryl groups.
 5. The compound of claim 4, wherein R₇₂, R₇₃, R₇₅, R₇₆,R₇₇, R₇₈, R₈₀, R₈₁, R₈₃, R₈₄, R₈₅, and R₈₆ are independently selectedfrom the group consisting of alkyl groups; and R₇₄ and R₈₂ areindependently selected from the group consisting of aryl groups.
 6. Thecompound of claim 5, wherein R₇₂, R₇₃, R₇₅, R₇₆, R₇₇, R₇₈, R₈₀, R₈₁,R₈₃, R₈₄, R₈₅, and R₈₆ are methyl groups; and R₇₄ and R₈₂ are phenylgroups.
 7. The compound of claim 1, wherein c is
 1. 8. The compound ofclaim 7, wherein R₇₂, R₇₃, R₇₅, R₇₆, R₇₇, R₇₈, R₈₀, R₈₁, R₈₃, R₈₄, R₈₅,and R₈₆ are methyl groups; and R₇₄ and R₈₂ are phenyl groups.
 9. Thecompound of claim 1, wherein c is 0; R₇₂, R₇₃, R₇₅, R₇₆, R₇₇, R₇₈, R₈₀,R₈₁, R₈₃, R₈₄, R₈₅, and R₈₆ are methyl groups; and R₇₄ and R₈₂ arephenyl groups.